Why does crude caffeine have a green tinge?

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Crude caffeine may have a green tinge because of the chlorophyll found naturally in tea leaves; these leaves are found in both ground and packaged tea. Caffeine can be ground from tea leaves, and the fresh leaves often used in the process contain more chlorophyll than dried ones.

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Crude caffeine from other sources may have a different coloration, depending on the presence or absence of chlorophyll in the source in question. Coffee beans do not display a green tinge when ground because they do not contain any chlorophyll.

Chlorophyll is a sticky liquid and may be released through grinding or crushing tea leaves. This can cause the green hue of the caffeine to intensify. Without crushing or grinding, the green color of the leaves is usually more mild. The shade of tea leaves also depends on the level of impurity.

Even caffeine recovered from dried and subsequently saturated tea leaves retains its greenish coloration. This may be done by introducing a base which reacts with the acids in the tea to form salts, causing the different substances in the tea to become isolated. Chlorophyll lasts a long time and can be partially reconstituted through contact with water, which brings out the color in strained or isolated tea leaves.